This application claims priority under 35 USC 119 of Japanese Patent Application No. 2000-352162 filed in JPO on Nov. 20, 2000, the entire disclosure of which is incorporated herein by reference. Japanese Patent Application No. 2000-352162 claims internal priority of Japanese Ok; Patent Application No. 11-366630 filed in JPO on Dec. 24, 1999.
1. Field of the Invention
The present invention relates to an image forming apparatus in which a reading unit is openably and closably provided on an image recording unit, and a platen cover is openably and closably provided on the reading unit.
2. Description of the Related Art
An image forming apparatus is provided with a reading unit on an.image recording unit, and the discharge tray storing the reading medium discharged from the image recording unit is provided in the space formed between the image recording unit and the reading unit. Moreover, the reading unit can be opened relative to the image recording unit in order to exchange a toner cartridge in the image recording unit and to eliminate the paper jam in the image recording unit. Further, a document is placed on platen glass provided on the upper surface of the image recording unit by opening the platen cover, so that the document is scanned.
This image forming apparatus is used as the electrophotographic copier and facsimile device. Users scan a document by lifting the platen cover, placing the document face down onto the platen glass, and then closing the platen cover. Then users typically press a start button in order to scan the document. The image data of the document scanned by the reading unit is transmitted to the image recording unit and the record is done on the recording paper. Additionally, when the paper jam is generated in the image recording unit or the toner cartridge is exchanged, the recording unit is opened using the hinge of the image recording unit as a supporting point and the maintenance is done. However, when the platen cover is parted even a little or the external power is added, the platen cover is opened widely and crashed into the wall which is in the opening direction, so that there is a possibility that the platen cover and the wall are broken. In particular, the platen cover, having the heavy load like the automatic document feeder (ADF), opens exponentially by the weight of the ADF, which may be broken with loud sound. Further, the platen cover having the heavy load like the ADF is provided with the assistant means like the spring for energizing to the opening direction in order for users to open the platen cover easily. However, this assistant means makes the platen cover open with vigor and the ADF provided in the platen cover crashes into the wall, so that the possibility of the breakage becomes higher.
It is an object of the present invention to prevent the above-mentioned problems and to provide an image forming apparatus including a lock unit for preventing a reading unit and a platen cover from being opened simultaneously.
According to the first aspect of the present invention, there is provided an image forming apparatus including a first lock unit for enabling the platen cover to be locked to the reading unit in the state in which the platen cover is closed, and a second lock unit for releasing the combination between the reading unit and the main body of the apparatus by interlocking with the first lock unit. Therefore, at the time of exchanging a process unit provided on the main body of the apparatus or swinging the reading unit for eliminating the recording paper jam in the reading part, the platen cover is locked to the reading unit, and the platen cover cannot be opened with the platen cover widely swung, so that the breakage of the platen cover can be prevented.
According to the second aspect of the present invention, the first lock unit is operated to the first position where the platen cover is locked to the reading unit and to the second position where the second lock unit is activated. Since the first lock unit causes interlocking so as to carry out the operation of releasing the lock between the main body of the apparatus and the reading unit by fixing the platen cover, one operation of the first lock unit make it possible to perform the release easily.
According to the third aspect of the present invention, a first lock unit includes the first lock member rotataby provided on the platen cover, and the lever for rotating the first lock member. Since the lever to the first lock member and an operation member corresponding with the second lock unit are provided on the first lock unit, the structure of the mechanism can be simpler.
According to the forth aspect of the present invention, the second lock unit restraining the first lock unit includes the link whose one end is rotatably supported by a shaft and which has an engagement part on the other end thereof for engaging the main body of the apparatus. The first lock member contacts against the link so as to release the engagement between the main body of the apparatus and the reading unit. Moreover, since the platen cover can be opened only in the state in which the reading unit is closed to the main body of the apparatus, the platen cover can be retained safely.
According to the fifth aspect of the present invention, there is provided an image forming apparatus including the operation lever for moving the first lock unit to the first position and the second position, and the stopper for stopping the operation lever, at the first position, which has been operated to the second position. The first lock unit has the first lock member which is freely rotatably installed on the reading unit and which is interlocked by the operation of the operation lever, and the engagement part of the platen cover for engaging with the first lock member. Moreover, the engagement of the reading unit and the platen cover is retained while working such as maintenance is being conducted with the recording part exposed, and the opening and closing of the platen cover can be permitted only in the state in which the reading unit precisely fixed to the main body of the apparatus.
According to the sixth aspect of the present invention, a second lock unit includes the second lock member which is installed on the reading unit and which interlocks with the first lock member through a link mechanism, and an engagement member provided on the main body of the apparatus for engaging with the second lock member. Therefore, the second lock unit is activated by the first lock unit, and the opening and closing of the reading unit relative to the main body of the apparatus becomes possible.
According to the seventh aspect of the present invention, there is provided an image forming apparatus including a stopper releasing member for releasing the engagement between the operation lever and the lever stopper that stops the operation lever at the first position when closing the reading unit provided on the upper part of the main body of the image forming apparatus. Moreover, the first lock member that was in the waiting position can be released from the stopped state through the interlocking mechanism by releasing the lever stopper locking the operation lever when closing the reading unit to the main body of the apparatus. Therefore, the state in which the platen cover is openable can be set easily.
Additional objects, aspects, benefits and advantages of the present invention will become apparent to those skilled in the art to which the present invention pertains from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings.